Semiconductor device and method for manufacturing semiconductor device

Abstract

A semiconductor device includes a first insulating resin member sealing a mounting surface of a lead frame, and a second insulating resin member sealing a heat dissipating surface. The second insulating resin member contains a filler having a maximum diameter of 0.02 mm to 0.075 mm. The second insulating resin member includes a thin molded portion formed in contact with the heat dissipating surface of the lead frame. The thin molded portion has a thickness 1.1 times to 2 times the maximum diameter of the filler. The semiconductor device includes, at an interface between the first insulating resin member and the second insulating resin member, a mixture layer in which these resins are mixed with each other.

The invention claimed is: 
     
       1. A semiconductor device including:
 a lead frame on which a semiconductor element is mounted; 
 a first insulating resin member sealing a mounting surface, of the lead frame, on which the semiconductor element is mounted; and 
 a second insulating resin member sealing a heat dissipating surface, of the lead frame, opposite to the mounting surface, wherein 
 the second insulating resin member contains a filler having a maximum diameter of 0.02 mm to 0.075 mm, and 
 the second insulating resin member includes a thin molded portion formed in contact with the heat dissipating surface of the lead frame, the thin molded portion having a thickness 1.1 times to 2 times the maximum diameter of the filler, 
 the semiconductor device includes, at an interface between the first insulating resin member and the second insulating resin member, a mixture layer in which a first material of the first insulating resin member and a second material of the second insulating resin member are mixed with each other. 
 
     
     
       2. The semiconductor device according to  claim 1 , wherein a lead frame space filled portion of the first insulating resin member is formed in an entire space between two separated regions of the lead frame. 
     
     
       3. The semiconductor device according to  claim 2 , wherein a contact surface between the first insulating resin member and the second insulating resin member in the two separated regions of the lead frame, and the heat dissipating surface are provided at a same level. 
     
     
       4. The semiconductor device according to  claim 1 , wherein a lead frame space filled portion of the second insulating resin member is provided between two separated regions of the lead frame,
 wherein the semiconductor device further comprises depressions and projections at a side surface of the lead frame on which the lead frame space filled portion is formed, and 
 wherein the depressions and projections are burrs. 
 
     
     
       5. The semiconductor device according to  claim 1 , wherein a roughened metal plating lead frame having a surface coated with roughened metal plating is used as the lead frame. 
     
     
       6. The semiconductor device according to  claim 1 , wherein the lead frame is coated with metal plating, and includes a scale-like portion obtained by distorting a surface of the metal plating into a scale form. 
     
     
       7. The semiconductor device according to  claim 6 , wherein at least one of the first insulating resin member and the second insulating resin member has a gate break mark, and the scale-like portion is disposed on a surface, of the lead frame, corresponding to the gate break mark. 
     
     
       8. The semiconductor device according to  claim 6 , wherein the scale-like portion is disposed at an outer peripheral portion of at least one of the mounting surface and the heat dissipating surface of the lead frame. 
     
     
       9. The semiconductor device according to  claim 6 , wherein the scale-like portion is disposed on an entire surface of at least one of the mounting surface and the heat dissipating surface of the lead frame. 
     
     
       10. The semiconductor device according to  claim 1 , wherein a resin having thermal conductivity higher than thermal conductivity of the first insulating resin member is used for the second insulating resin member. 
     
     
       11. The semiconductor device according to  claim 1 , wherein an insulating resin having thermal conductivity of 3 W/m·K to 12 W/m·K is used for the second insulating resin member. 
     
     
       12. The semiconductor device according to  claim 11 , wherein an insulating resin having thermal conductivity of 3 W/m·K to 12 W/m·K is used for the first insulating resin member. 
     
     
       13. The semiconductor device according to  claim 1 , wherein a heat sink is joined to a surface, of the thin molded portion, opposite to a surface, of the thin molded portion, facing the heat dissipating surface of the lead frame, such that a junction area of the heat sink is smaller than a heat dissipation side area of the thin molded portion. 
     
     
       14. The semiconductor device according to  claim 1 , wherein a frame-like projecting portion is provided at an outer peripheral end portion of the second insulating resin member, and the thin molded portion is integrally formed within the frame-like projecting portion. 
     
     
       15. A method for manufacturing a semiconductor device, the method comprising:
 molding a powder-like second insulating resin into a sheet-like second insulating resin by using a resin molder; 
 transferring the sheet-like second insulating resin to a position above a lower die while being disposed on the resin molder, and placing the sheet-like second insulating resin on the lower die; 
 disposing a lead frame on which a semiconductor element is mounted, on the sheet-like second insulating resin disposed on the lower die; and 
 mounting an upper die to the lower die, and performing transfer molding to form a first insulating resin member sealing a mounting surface, of the lead frame, on which the semiconductor element is mounted, and a second insulating resin member sealing a heat dissipating surface, of the lead frame, opposite to the mounting surface. 
 
     
     
       16. A method for manufacturing a semiconductor device, the method comprising:
 molding a powder-like second insulating resin into a sheet-like second insulating resin on a heat sink by using a resin molder; 
 transferring the sheet-like second insulating resin molded on the heat sink to a position above a lower die while being disposed on the resin molder together with the heat sink, and placing the sheet-like second insulating resin and the heat sink on the lower die; 
 disposing a lead frame on which a semiconductor element is mounted, on the sheet-like second insulating resin and the heat sink disposed on the lower die; and 
 mounting an upper die to the lower die, and performing transfer molding, thereby forming a first insulating resin member sealing a mounting surface, of the lead frame, on which the semiconductor element is mounted, and a second insulating resin member sealing a heat dissipating surface, of the lead frame, opposite to the mounting surface, and joining the heat sink to the second insulating resin member. 
 
     
     
       17. The method for manufacturing the semiconductor device according to  claim 15 , further comprising, before the semiconductor element is mounted on the mounting surface of the lead frame, forming metal plating on a surface of the lead frame, and subjecting the metal plating to laser irradiation to form a scale-like portion in which the surface of the metal plating is distorted into a scale form. 
     
     
       18. The method for manufacturing the semiconductor device according to  claim 16 , further comprising, before the semiconductor element is mounted on the mounting surface of the lead frame, forming metal plating on a surface of the lead frame, and subjecting the metal plating to laser irradiation to form a scale-like portion in which the surface of the metal plating is distorted into a scale form. 
     
     
       19. The semiconductor device according to  claim 2 , wherein a roughened metal plating lead frame having a surface coated with roughened metal plating is used as the lead frame. 
     
     
       20. The semiconductor device according to  claim 2 , wherein the lead frame is coated with metal plating, and includes a scale-like portion obtained by distorting a surface of the metal plating into a scale form.